A Technique for Displaying Theoretical Transmission Electron Microscope Images

1971 ◽  
Vol 29 ◽  
pp. 96-97
Author(s):  
P. J. Fillingham ◽  
H. J. Leamy ◽  
D. M. Maher
Keyword(s):  
Electron Microscope ◽  
Magnetic Tape ◽  
Dark Field Image ◽  
Diffraction Theory ◽  
Dark Field ◽  
Transmission Electron ◽  
High Quality Image ◽  
Microscope Images ◽  
Analog Form ◽  
Theoretical Intensity

Since the earliest work on computer simulation of electron microscope images, it has been realized that a technique for producing a high quality image would facilitate analysis of the information content of theoretical intensity data. In particular, this would be an aid in image analysis and testing approximations used in electron diffraction theory.A technique has been developed for producing a semiglossy print from data on magnetic tape using a commercial facsimile device. In the present application only the receiver of the facsimile device is used to produce a simulated electron micrograph. An array of intensities corresponding to the light or dark field image of a defect is computed. A simple two-dimensional interpolation scheme gives an enlarged array (on magnetic tape) which is then converted to analog form and transmitted to the receiver of the facsimile device.

Observation of Atom Images by Means of Field Emission Stem

1976 ◽  
Vol 34 ◽  
pp. 500-501
Author(s):  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda
Keyword(s):  
Electron Microscope ◽  
Carbon Film ◽  
Dark Field Image ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Single Atom ◽  
Bright Field Image ◽  
Contrast Effects ◽  
Transmission Electron ◽  
Scanning Transmission

A number of studies of single atom image observation utilizing either scanning transmission electron microscope ( STEM ) or conventional electron microscope ( OEM ) have been reported. For this purpose, the dark field image observation seems more promising because the scattering cross-section of an atom is extremely small. Much attention has been paid to decreasing background noises resulting from the supporting film. A thin amorphous carbon film is often utilized as a supporting film. However, many high contrast spots appear even in the dark field image when OEM is used. Matsuda and Nagata3 applied an incoherent illumination technique to the bright field image observation of OEM, and succeeded, in removing the phase contrast effects from the image.

Transmission Electron Microscopy of II-VI/III-V Semiconductor Heteroepitaxial Interfaces

1989 ◽  
Vol 161 ◽  
Author(s):  
D. Li ◽  
N. Otsuka ◽  
J. Qiu ◽  
J. Glenn ◽  
M. Kobayashi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Molecular Beam ◽  
Dark Field ◽  
Group Iii ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Microscope Images ◽  
High Resolution Electron Microscope

ABSTRACTInterfaces of pseudomorphic (100)ZnSe/GaAs and (100)CdTe/InSb heterostructures grown by molecular beam epitaxy have been studied by transmission electron microscopy. High resolution electron microscope images show dark bands with thicknesses of one or two monolayers at the interfaces. The interfaces appear as bright lines in dark field images of the 200 type reflections, while they become dark lines in dark field images of the 400 type reflections. These observations are explained by assuming the existence of interfaces layers of III2VI3 compounds which have structural vacancies in the sublattices of the group III atoms.

Resolution in the Scanning Transmission Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 454-455
Author(s):  
M. G. R. Thomson
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Spherical Aberration ◽  
Signal To Noise Ratio ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Objective Lens ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The variation of contrast and signal to noise ratio with change in detector solid angle in the high resolution scanning transmission electron microscope was discussed in an earlier paper. In that paper the conclusions were that the most favourable conditions for the imaging of isolated single heavy atoms were, using the notation in figure 1, either bright field phase contrast with β0⋍0.5 α0, or dark field with an annular detector subtending an angle between ao and effectively π/2.The microscope is represented simply by the model illustrated in figure 1, and the objective lens is characterised by its coefficient of spherical aberration Cs. All the results for the Scanning Transmission Electron Microscope (STEM) may with care be applied to the Conventional Electron Microscope (CEM). The object atom is represented as detailed in reference 2, except that ϕ(θ) is taken to be the constant ϕ(0) to simplify the integration. This is reasonable for θ ≤ 0.1 θ0, where 60 is the screening angle.

Interlayer mixing in GaAs/AlxGa1-xAs heterostructures as a result of Se+ ion implantation

1988 ◽  
Vol 46 ◽  
pp. 908-909
Author(s):  
E.G. Bithell ◽  
W.M. Stobbs
Keyword(s):  
Ion Implantation ◽  
Diffusion Coefficients ◽  
Dark Field ◽  
Atomic Mass ◽  
Composition Profile ◽  
Semiconductor Heterostructures ◽  
Transmission Electron ◽  
Microscope Images ◽  
Damage Process ◽  
Electron Energy Loss

It is well known that the microstructural consequences of the ion implantation of semiconductor heterostructures can be severe: amorphisation of the damaged region is possible, and layer intermixing can result both from the original damage process and from the enhancement of the diffusion coefficients for the constituents of the original composition profile. A very large number of variables are involved (the atomic mass of the target, the mass and energy of the implant species, the flux and the total dose, the substrate temperature etc.) so that experimental data are needed despite the existence of relatively well developed models for the implantation process. A major difficulty is that conventional techniques (e.g. electron energy loss spectroscopy) have inadequate resolution for the quantification of any changes in the composition profile of fine scale multilayers. However we have demonstrated that the measurement of 002 dark field intensities in transmission electron microscope images of GaAs / AlxGa1_xAs heterostructures can allow the measurement of the local Al / Ga ratio.

scholarly journals Characteristics of multiwalled carbon nanotubes-rhenium nanocomposites with varied rhenium mass fractions

2017 ◽  
Vol 7 ◽  
pp. 184798041770717 ◽  
Author(s):  
Anna D Dobrzańska-Danikiewicz ◽  
Weronika Wolany ◽  
Dariusz Łukowiec ◽  
Karolina Jurkiewicz ◽  
Paweł Niedziałkowski
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Multiwalled Carbon Nanotubes ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Multiwalled Carbon ◽  
Weight Percentage ◽  
Transmission Electron ◽  
Scanning Transmission

The purpose of the article is to discuss the process of oxidation of carbon nanotubes subsequently subjected to the process of decoration with rhenium nanoparticles. The influence of functionalization in an oxidizing medium is presented and the results of investigations using Raman spectroscopy and infrared spectroscopy are discussed. Multiwalled carbon nanotubes rhenium-type nanocomposites with the weight percentage of 10%, 20% and 30% of rhenium are also presented in the article. The structural components of such nanocomposites are carbon nanotubes decorated with rhenium nanoparticles. Microscopic examinations under transmission electron microscope and scanning transmission electron microscope using the bright and dark field confirm that nanocomposites containing about 20% of rhenium have the most homogenous structure.

HREM and HAADF Studies of Precipitates in the Mg-Y-Nd Alloy System

2007 ◽  
Vol 561-565 ◽  
pp. 275-278
Author(s):  
Wei Sun ◽  
Li Sun ◽  
Lin Lin Liu ◽  
Ze Zhang
Keyword(s):  
Structural Model ◽  
Imaging Technique ◽  
Dark Field Image ◽  
Alloy System ◽  
Dark Field ◽  
Orthorhombic Unit Cell ◽  
Characteristic Distribution ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Image Technique

By means of high resolution transmission electron microscopy (HREM) and high-angle annular dark-field image technique (HAADF), morphological, structural and compositional characteristics of the precipitates in the Mg-4Y-3Nd alloy aged at 200°C for different periods of time have been studied. On the basis of HREM observations, an atomic structural model for the β’-precipitate with an orthorhombic unit cell has been proposed. The characteristic distribution of the precipitates which are rich in rare-earth elements (Y, Nd) has been clearly revealed by the HAADF imaging technique.

Microstructural Characterization of an Al-Mg-Si Aluminum Alloy Processed by Equal Channel Angular Pressing

2013 ◽  
Vol 745-746 ◽  
pp. 303-308
Author(s):  
Zhen Zhang ◽  
Man Ping Liu ◽  
Ying Da Yu ◽  
Pål C. Skaret ◽  
Hans Jørgen Roven
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
High Resolution ◽  
Dislocation Density ◽  
Equal Channel Angular Pressing ◽  
Transmission Electron Microscope ◽  
Microstructural Characterization ◽  
Dark Field ◽  
Angular Pressing ◽  
Transmission Electron

In the present work, a peak-aged 6061 Al-Mg-Si aluminum alloy was subjected to equal channel angular pressing (ECAP) at 110 °C. The microstructure of the sample was characterized by high-resolution transmission electron microscope and weak-beam dark-field method. It was shown that the dislocation density in some local areas is much lower than the average dislocation density expected in the usual alloys processed by severe plastic deformation. High-resolution transmission electron microscope observations indicated that many full dislocations were dissociated into partial dislocations connected by stacking faults. In addition, a Z-shaped defect (i.e., a type of dislocation locks) probably formed by the reactions of the partials in different {111} planes was first observed in the ECAPed alloy. Furthermore, the precipitation behavior and sequence in the present ECAPed sample were identified by high-resolution transmission electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document